Jump to content

Anyone else's bike do this?


Recommended Posts

When the throttle is barely held open, around 1/8th open or so, the thing stutters and misses at mid to high rpms. Low rpm it runs smooth as silk but once the revs get up it starts to miss when held steady at the low throttle opening. Roll on the throttle at all and it pulls and takes off very smooth and strong. It is more evident in taller gears. Third works great for testing it.

I have an 02 WR with an 03 YZ cam and timing (ofcourse). I run 02 YZ stock jetting, including the PAJ. I did all the free mods as well.

I am wondering if this might have something to do with the ACV (coast enricher). I bypassed mine by removing the o-ring and plugging that vacuum hole with a nice circular plug, and then spun the diaphragm around so that the pin faces the opposite direction and left spring in place.

It has done this for awhile but it was only bothersome when I spent way too much time on dirt roads this weekend for long periods of time.

I did a search and read for a few hours and found some people with a similiar complaint but did not read of any fixes.

Link to comment
Share on other sites

I pretty much have the same set up as you (except jetting)and I don't have any problems. I started with stock YZF jetting but then adjusted for my conditions.

You are probably a little lean on the pilot circuit. Start by adjusting fuel screw (out). Maybe one larger PJ and then readjust fuel screw. I use a 42 PJ and 17/8 out on fuel screw.

Link to comment
Share on other sites

Ok I put the air cut valve back to factory and the problem totally went away. The only possible difference it could be was that it was about 10-15 degrees cooler here today than it has been.

Rick how did you bypass your ACV?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...